Sowing Seeds Indoors – The Do’s and Donts

Sowing Seeds Indoors.

Seedlings

The first of our Seed Sowing guides will focus mainly on sowing seeds indoors. Whether it be on a sunny windowsill, heated propagator or in a seed sowing greenhouse, the principals are basically the same.

Why do we sow seeds indoors?

There are many advantages to sowing seeds indoors/ under glass. The added protection they gain from the cold and windy weather at this time of year allows for some of the more tender seedlings to establish themselves. When the outside temperatures rise enough to start planting seeds outdoors (normally around May-June), the seedlings started indoors, will be sturdy enough to plant out. Meaning the seedlings will ultimately spend less time reaching maturity when they are eventually planted out, allowing you to maximize yields and save on space.

Mini Propagators, Seed Sowing tray, and Compost

When can I sow seeds indoors/ under glass?

If your lucky enough to have a large warm windowsill, heated greenhouse/ propagator, then it is possible to start some seeds as early as January. When sowing seeds indoors it’s important to make sure the temperature is consistently around the 13° – 22° mark. When planting any seeds, it is important to pay close attention at the information/ growing guides printed on the packaging. These guides normally provide you with an Indoor sowing date, an outdoor sowing date, and a planting out date. While the temperatures in parts of the UK and Ireland can vary greatly, these are often just a rough guide, and you will soon learn how to work with the weather in your local climate.

What seeds can I sow indoors?

You can technically grow any seeds indoors, but some will appreciate the extra heat and warmth more than others.

Tomatoes

Peppers

Okra

Aubergine

Chillies

Lettuce

Kale

Swiss Chard

Khorabi

Herbs

All of these seedlings are susceptible to a cold frost and are often much better starting indoors at least until the last frosts have cleared.

What can I sow my seeds in?

There are any number of different sized plug trays, pots, and containers designed for sowing seeds. Basically, if you can put soil in it, and it is not too small then you can sow seeds in it. A garden shop bought seed tray will work just as well as an empty yogurt pot. Seed trays are inexpensive and we tend to get ours from discount/pound shops. They are also reusable, noting it is important to clean them thoroughly after each growing season, to avoid cross contamination and spreading any diseases. Using designated seed trays and plug trays are handy, as it’s possible to purchase existing plastic or glass covers to the correct size, and are often designed to fit the shape of a standard windowsill.

The size of the seeds often determine the size of the container that you sow your seeds in.

Small Seeds e.g. herbs, cauliflower, broccoli. I often sow these randomly over a seed tray, and once the seedlings have started to develop a true leaf, are often pricked out into larger containers.

Medium-sized seeds e.g. Peppers, Chillies, Lettuce. I often sow one or two at a time into an individual plug. The reason why I sow two at a time instead of one is in case one of the seeds doesn’t germinate. If both seeds germinate then one is removed. I often use these individual plugs to keep trays of lettuce and salad crops ready to fill up any gaps or empty spaces I might have within the plot.

Large Seeds e.g. Courgettes, Pumpkins, and Sweetcorn. I often sow these into small individual pots ( 3” – 5”) as they require more growing space for their root systems to get well established.

Sowing seeds

What is the best type of soil to sow seeds in?

Seeds can be sown in any soil, buy you are much better off starting your seedlings in a seed sowing & cutting compost. These composts are sieved well and contain fewer larger pieces of bark and stones, anything that may restrict a seedlings growth. They often contain large quantities of loam, allowing the compost to retain moisture while repelling nutrients which can be harmful to seedlings.

Heated Propagator

There are no right or wrong ways when it comes to sowing seeds. And you will soon realize that some just work better than others. The winter can be a very long period for keep vegetable growers. Starting some seeds indoors and caring for them, helps take the edge off until Spring time comes. Over time you will find your own preferred methods, containers and sowing compost that works best for you.

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